title: The embryonic cell lineage of the nematode Rhabditophanes sp.
abstract: One of the unique features of the model organism Caenorhabditis elegans is its invariant development, where a stereotyped cell lineage generates a fixed number of cells with a fixed cell type. It remains unclear how embryonic development evolved within the nematodes to give rise to the complex, invariant cell lineage of C. elegans. Therefore, we determined the embryonic cell lineage of the nematode, Rhabditophanes sp. (family Alloionematidae) and made detailed cell-by-cell comparison with the known cell lineages of C. elegans, Pellioditis marina and Halicephalobus gingivalis. This gave us a unique data set of four embryonic cell lineages, which allowed a detailed comparison between these cell lineages at the level of each individual cell. This lineage comparison revealed a similar complex polyclonal fate distribution in all four nematode species (85% of the cells have the same fate). It is striking that there is a conservation of a 'C. elegans' like polyclonal cell lineage with strong left-right asymmetry. We propose that an early symmetry-breaking event in nematodes of clade IV-V is a major developmental constraint which shapes their asymmetric cell lineage.
authors.affiliation: Department of Biology, Ghent University, Ghent, Belgium.
authors.forename: Wouter
authors.initials: W
authors.lastname: Houthoofd
authors.forename: Maxime
authors.initials: M
authors.lastname: Willems
authors.forename: Kim
authors.initials: K
authors.lastname: Jacobsen
authors.forename: August
authors.initials: A
authors.lastname: Coomans
authors.forename: Gaetan
authors.initials: G
authors.lastname: Borgonie
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000166:cytology / Q000196:embryology; D019070:Cell Lineage; D004625:Embryo, Nonmammalian / Q000166:cytology* / Q000196:embryology; D008954:Models, Biological; D009348:Nematoda / Q000166:cytology* / Q000196:embryology; D013045:Species Specificity